It is not just the Marines, but the Rangers like LAWs over the AT4. You can collapse the LAW and stuff it into your rucksack for a jump. The AT4 you gotta strap to your side.
If the balloon goes up, there are enough LAWs to go 'round so that every Ranger could pack a LAW in their ruck. SOP was that once you completed your PLF & yanked the quick-release on the one riser, you unlimbered your primary weapon, stuffed your chute away in the bag, and then unlimbered the LAW. Then, you ran to the AA, ruck on back, a LAW under one arm & rifle under the other arm.